Light-emitting element and light-emitting device

Abstract

To provide a light-emitting element and a light-emitting device, capable of reducing leakage current flowing between electrodes of a plurality of light-emitting parts.SOLUTION: A third nitride semiconductor layer of a second light-emitting part includes: a first layer; a second layer located between a second nitride semiconductor layer of the first light-emitting part and the first layer; and a third layer located between the first layer and a second active layer of the second light-emitting part. The first layer includes at least one selected from a group consisting of Be, Mg, Ca, Fe, Zn, and C. A thickness of the third layer is greater than a thickness of the second layer. A first electrode is connected to a first nitride semiconductor layer of the first light-emitting part, a second electrode is connected to the third layer, a third electrode is connected to the second layer, and a fourth electrode is connected to a fourth nitride semiconductor layer of the second light-emitting part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light-emitting element and a light-emitting device. [Background technology]

[0002] For example, as disclosed in Patent Document 1, there is a light emitting device in which a plurality of active layers are stacked on a substrate via a tunnel junction layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] European Patent Application Publication No. 4086964 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a light emitting element and a light emitting device that can reduce leakage current flowing between electrodes of a plurality of light emitting portions. [Means for solving the problem]

[0005] According to one aspect of the present invention, a light-emitting device includes: a first light-emitting section having a first nitride semiconductor layer containing a first conductive type impurity, a second nitride semiconductor layer containing a second conductive type impurity, and a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer; a second light-emitting section located on the second nitride semiconductor layer and having a third nitride semiconductor layer, a fourth nitride semiconductor layer containing a second conductive type impurity, and a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer; a first electrode, a second electrode, a third electrode, and a fourth electrode, wherein the third nitride semiconductor layer is a first layer, a second layer located between the second nitride semiconductor layer and the first layer and containing a first conductivity type impurity; and a third layer located between the first layer and the second active layer and containing a first conductivity type impurity, wherein the first layer contains at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C, the third layer is thicker than the second layer, the first electrode is connected to the first nitride semiconductor layer, the second electrode is connected to the third layer, the third electrode is connected to the second layer, and the fourth electrode is connected to the fourth nitride semiconductor layer.

[0006] According to one aspect of the present invention, a light-emitting element includes a first structure, a second structure, and a third structure, the first structure including a first stacked portion including a first nitride semiconductor layer containing a first conductivity type impurity, a second nitride semiconductor layer containing a second conductivity type impurity, a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer, and a third nitride semiconductor layer disposed on the second nitride semiconductor layer and containing the first conductivity type impurity, a first electrode connected to the first nitride semiconductor layer, and a second electrode connected to the third nitride semiconductor layer, The third structure includes a second stacked layer having the first stacked layer, a fourth nitride semiconductor layer containing second conductive type impurities, a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer, and a fifth nitride semiconductor layer disposed on the fourth nitride semiconductor layer and containing first conductive type impurities, a third electrode connected to the third nitride semiconductor layer, and a fourth electrode connected to the fifth nitride semiconductor layer, and the third structure includes the first stacked layer, the second stacked layer, a sixth nitride semiconductor layer containing second conductive type impurities, and a fifth nitride semiconductor layer disposed on the fifth nitride semiconductor layer and containing first conductive type impurities. a third stacked portion having a third active layer located between the fifth nitride semiconductor layer and the sixth nitride semiconductor layer, a fifth electrode connected to the fifth nitride semiconductor layer, and a sixth electrode connected to the sixth nitride semiconductor layer, wherein the third nitride semiconductor layer of the second structure has a first layer, a second layer located between the second nitride semiconductor layer and the first layer, and a third layer located between the first layer and the second active layer, the first layer containing at least one element selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C, and the thickness of the third layer is greater than the thickness of the second layer. the fifth nitride semiconductor layer of the third structure has a fourth layer, a fifth layer located between the fourth nitride semiconductor layer and the fourth layer, and a sixth layer located between the fourth layer and the third active layer, the fourth layer contains at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C, the sixth layer is thicker than the fifth layer, the first stacked portion of the first structure is a first light-emitting portion, the second stacked portion of the second structure is a second light-emitting portion, and the third stacked portion of the third structure is a third light-emitting portion.

[0007] According to one aspect of the present invention, a light-emitting device includes a wiring substrate having a first wiring section that supplies current between the third electrode and the first electrode and a second wiring section that supplies current between the fourth electrode and the second electrode, and one or more light-emitting elements described in any one of claims 1 to 3 that are arranged on the wiring substrate, and does not include a wavelength conversion member containing a phosphor. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a light emitting element and a light emitting device that can reduce leakage current flowing between electrodes of a plurality of light emitting portions. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view of a light-emitting element according to a first embodiment. [Figure 2A] 1 is a schematic cross-sectional view of a portion of a light-emitting device according to a first embodiment. [Figure 2B] 1 is a schematic cross-sectional view of a portion of a light-emitting device according to a first embodiment. [Figure 3A] 1 is a schematic cross-sectional view of a portion of a light-emitting device according to a first embodiment. [Figure 3B] 1 is a schematic cross-sectional view of a portion of a light-emitting device according to a first embodiment. [Figure 4] FIG. 5 is a schematic cross-sectional view of a light-emitting element according to a second embodiment. [Figure 5A] FIG. 10 is a schematic cross-sectional view of a part of a light-emitting device according to a second embodiment. [Figure 5B] FIG. 10 is a schematic cross-sectional view of a part of a light-emitting device according to a second embodiment. [Figure 6A] FIG. 10 is a schematic cross-sectional view of a part of a light-emitting device according to a second embodiment. [Figure 6B] FIG. 10 is a schematic cross-sectional view of a part of a light-emitting device according to a second embodiment. [Figure 7] 1 is a schematic cross-sectional view of a light emitting device according to an embodiment. [Figure 8] 3 is a schematic cross-sectional view illustrating one step of the method for manufacturing the light-emitting element according to the first embodiment. FIG. [Figure 9]3 is a schematic cross-sectional view illustrating one step of the method for manufacturing the light-emitting element according to the first embodiment. FIG. [Figure 10] 3 is a schematic cross-sectional view illustrating one step of the method for manufacturing the light-emitting element according to the first embodiment. FIG. [Figure 11] 3 is a schematic cross-sectional view illustrating one step of the method for manufacturing the light-emitting element according to the first embodiment. FIG. [Figure 12] 3 is a schematic cross-sectional view illustrating one step of the method for manufacturing the light-emitting element according to the first embodiment. FIG. [Figure 13] 3 is a schematic cross-sectional view illustrating one step of the method for manufacturing the light-emitting element according to the first embodiment. FIG. [Figure 14] FIG. 4 is a schematic cross-sectional view of a light-emitting device according to a modified example of the first embodiment. [Figure 15] 10 is a graph showing an example of behavior of current density with respect to voltage in a second light-emitting section of the light-emitting element according to the first embodiment. [Figure 16] 10 is a graph showing an example of a SIMS analysis of a wafer sample having the layer structure shown in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. The dimensions, materials, shapes, relative positions, and the like of components described in the embodiments are not intended to be limiting unless otherwise specified, and are merely illustrative examples. The sizes and positional relationships of components shown in each drawing may be exaggerated for clarity. In the following description, the same names and symbols indicate the same or similar components, and detailed descriptions will be omitted as appropriate. Cross-sectional views may also be shown as end views showing only the cut surface.

[0011] In the following description, terms indicating specific directions or positions (e.g., "above," "below," and other terms including these terms) may be used. However, these terms are used merely to facilitate understanding of relative directions or positions in the referenced drawings. As long as the relative direction or position relationship indicated by terms such as "above" and "below" in the referenced drawings is the same, the arrangement in drawings other than those disclosed herein, actual products, etc., may not be the same as in the referenced drawings. In this specification, the positional relationship expressed as "above (or below)" includes, for example, when two components are assumed to exist, a case in which the two components are in contact with each other, and a case in which the two components are not in contact with each other and one component is located above (or below) the other component. In addition, in this specification, the thickness of a layer refers to the maximum thickness of that layer.

[0012] In this specification, the semiconductor layer and the active layer are made of a nitride semiconductor. x Al y Ga 1-x-y The term "nitride semiconductor" includes all semiconductors with compositions in which the composition ratios x and y in the chemical formula N (0≦x≦1, 0≦y≦1, x+y≦1) are varied within their respective ranges. In addition, the term "nitride semiconductor" also includes semiconductors with the above chemical formula that further contain Group V elements other than N (nitrogen), and semiconductors that further contain various elements added to control various physical properties such as conductivity type.

[0013] In this specification, the first conductivity type will be described as n-type and the second conductivity type as p-type. As the first conductivity type impurity (i.e., n-type impurity), for example, Si (silicon) or Ge (germanium) can be used. As the second conductivity type impurity (i.e., p-type impurity), for example, Mg (magnesium) can be used. Note that the first conductivity type may be p-type and the second conductivity type may be n-type. In this case, in the electrodes described below, the cathode will be read as the anode. Also, the anode may be read as the cathode.

[0014] [First embodiment] 1 to 3B, a light-emitting element 1 according to a first embodiment will be described. The light-emitting element 1 is a light-emitting diode. As shown in FIG. 1, the light emitting element 1 includes a first light emitting section 101, a second light emitting section 102, a first electrode 71, a second electrode 72, a third electrode 73, and a fourth electrode 74.

[0015] <First light-emitting unit 101> The first light emitting unit 101 has a first nitride semiconductor layer 10 containing a first conductivity type impurity, a second nitride semiconductor layer 20 containing a second conductivity type impurity, and a first active layer 61 located between the first nitride semiconductor layer 10 and the second nitride semiconductor layer 20. The first active layer 61 is a light emitting layer that emits light, and has, for example, an MQW (Multiple Quantum Well) structure that includes a plurality of barrier layers and a plurality of well layers. The well layers of the first active layer 61 are, for example, In x1 Ga 1-x1 N (0≦x1≦1). The concentration of the first conductivity type impurity contained in the first nitride semiconductor layer 10 is, for example, 1×10 18 cm -3 More than 1×10 19 cm -3 The concentration of the second conductivity type impurity contained in the second nitride semiconductor layer 20 may be, for example, 1×10 18 cm -3 More than 1×10 20 cm -3 It may be the following:

[0016] The first nitride semiconductor layer 10 has a first surface 10A located on the opposite side to the interface with the first active layer 61. The light-emitting element 1 may have a substrate on the first surface 10A side. The first nitride semiconductor layer 10 also has a first connecting surface 10B exposed from the first active layer 61, the second nitride semiconductor layer 20, and the second light-emitting portion 102. The first connecting surface 10B is located on the opposite side to the first surface 10A.

[0017] <Second light-emitting unit 102> The second light emitting section 102 is located on the second nitride semiconductor layer 20 of the first light emitting section 101. The second light emitting section 102 has a third nitride semiconductor layer 30 located on the second nitride semiconductor layer 20, a fourth nitride semiconductor layer 40 containing second conductivity type impurities, and a second active layer 62 located between the third nitride semiconductor layer 30 and the fourth nitride semiconductor layer 40. The second active layer 62 is a light emitting layer that emits light, and has, for example, an MQW structure. The well layer of the second active layer 62 is, for example, In x2 Ga 1-x2 N (0≦x2≦1). x2 may be larger than x1. In the case of an MQW structure, there is only required to be at least one layer where x2>x1. This allows the second active layer 62 to emit light of a different wavelength compared to the first active layer 61. The concentration of the second conductivity type impurity contained in the fourth nitride semiconductor layer 40 is, for example, 1×10 18 cm -3 More than 1×10 20 cm -3 It may be the following:

[0018] The third nitride semiconductor layer 30 has a second connecting surface 30B and a third connecting surface 30A. The second connecting surface 30B and the third connecting surface 30A are exposed from the second active layer 62 and the fourth nitride semiconductor layer 40. The third nitride semiconductor layer 30 has a first layer 31, a second layer 32, and a third layer 33. The detailed configurations of these layers 31 to 33 will be described later. The second connecting surface 30B is a partial surface of the third layer 33. The third connecting surface 30A is a partial surface of the second layer 32.

[0019] The fourth nitride semiconductor layer 40 has a fourth connecting surface 40A located on the opposite side to the interface with the second active layer 62.

[0020] <First electrode 71> The first electrode 71 is disposed on the first connection surface 10B of the first nitride semiconductor layer 10 and is electrically connected to the first nitride semiconductor layer 10. The material of the first electrode 71 can be, for example, at least one selected from the group consisting of titanium, aluminum, platinum, rhodium, ruthenium, and gold. The first electrode 71 may be, for example, a combination of titanium, aluminum, and platinum. Note that the materials of the other electrodes described below can also be, for example, the same materials as the first electrode 71.

[0021] <Second electrode 72> The second electrode 72 is disposed on the second connecting surface 30B of the third nitride semiconductor layer 30 and is electrically connected to the third layer 33 of the third nitride semiconductor layer 30.

[0022] <Third electrode 73> The third electrode 73 is disposed on the third connecting surface 30A of the third nitride semiconductor layer 30 and is electrically connected to the second layer 32 of the third nitride semiconductor layer 30.

[0023] <4th electrode 74> The fourth electrode 74 is disposed on the fourth connection surface 40A of the fourth nitride semiconductor layer 40 and is electrically connected to the fourth nitride semiconductor layer 40.

[0024] The third electrode 73 functions as an anode of the first light-emitting unit 101. The first electrode 71 functions as a cathode of the first light-emitting unit 101. When a current is supplied to the first active layer 61 through the third electrode 73 and the first electrode 71, the first active layer 61 emits light. The emission peak wavelength of the first active layer 61 is the first wavelength. The first wavelength is, for example, 360 nm or more and 550 nm or less, and preferably 440 nm or more and 470 nm or less. However, the range of the first wavelength is not limited to this.

[0025] The fourth electrode 74 functions as an anode of the second light-emitting unit 102. The second electrode 72 functions as a cathode of the second light-emitting unit 102. When a current is supplied to the second active layer 62 through the fourth electrode 74 and the second electrode 72, the second active layer 62 emits light. The emission peak wavelength of the second active layer 62 is a second wavelength that is different from the first wavelength of the first active layer 61. The second wavelength is, for example, 450 nm or more and 700 nm or less, and preferably 570 nm or more and 590 nm or less. However, the range of the second wavelength is not limited to this.

[0026] The light emitted by the first active layer 61 and the light emitted by the second active layer 62 are extracted to the outside of the light-emitting element 1 mainly from the first surface 10A side of the first nitride semiconductor layer 10.

[0027] In the light-emitting element 1, it is possible to switch between a first light-emitting state in which the first light-emitting section 101 emits light and the second light-emitting section 102 does not emit light, a second light-emitting state in which the second light-emitting section 102 emits light and the first light-emitting section 101 does not emit light, and a third light-emitting state in which the first light-emitting section 101 and the second light-emitting section 102 emit light simultaneously, by controlling an external circuit.

[0028] In the third state, the light-emitting element 1 emits visible light that is a mixture of light of the first wavelength emitted by the first active layer 61 and light of the second wavelength emitted by the second active layer 62. The light-emitting element 1 emits, for example, white light. The color temperature (including the correlated color temperature) of the white light is, for example, 3000 K or more and 7000 K or less.

[0029] When the first active layer 61 is caused to emit light, a positive potential is applied to the third electrode 73, and a potential lower than that of the third electrode 73 is applied to the first electrode 71, and a reverse voltage is applied to the pn junction between the second nitride semiconductor layer 20 containing second-conductivity-type impurities (p-type impurities) and the second layer 32 containing first-conductivity-type impurities (n-type impurities). According to this embodiment, the light-emitting element 1 includes a tunnel junction between the second nitride semiconductor layer 20 and the second layer 32. By increasing the impurity concentration in the pn junction between the second nitride semiconductor layer 20 and the second layer 32, the width of the depletion layer formed by the pn junction is narrowed. This allows electrons present in the valence band of the p-type second nitride semiconductor layer 20 to tunnel into the conduction band of the n-type second layer 32, making it easier to flow current from the third electrode 73 to the first electrode 71.

[0030] The second nitride semiconductor layer 20 and the second layer 32 may be directly bonded to each other. Alternatively, the light-emitting element 1 may further include a fifth nitride semiconductor layer 50 located between the second nitride semiconductor layer 20 and the second layer 32. The fifth nitride semiconductor layer 50 contains first-conductivity-type impurities (n-type impurities) and forms an interface (p-n junction) with the second nitride semiconductor layer 20. The maximum concentration of the first-conductivity-type impurities contained in the fifth nitride semiconductor layer 50 is higher than the maximum concentration of the first-conductivity-type impurities contained in the first nitride semiconductor layer 10 and the maximum concentration of the first-conductivity-type impurities contained in the third nitride semiconductor layer 30. This narrows the width of the depletion layer formed by the p-n junction between the second nitride semiconductor layer 20 and the fifth nitride semiconductor layer 50, making it easier for electrons present in the valence band of the second nitride semiconductor layer 20 to tunnel to the second layer 32. The concentration of the first-conductivity-type impurities contained in the fifth nitride semiconductor layer 50 is, for example, 1×10 18 cm -3 More than 1×10 20 cm -3 or less, or 1×10 18 cm -3 More than 1×10 19 cm -3 It may be the following:

[0031] (Third nitride semiconductor layer 30) The first layer 31, the second layer 32, and the third layer 33 of the third nitride semiconductor layer 30 will be described in detail.

[0032] The first layer 31 is located between the second layer 32 and the third layer 33. The first layer 31 contains at least one selected from the group consisting of Be (beryllium), Mg (magnesium), Ca (calcium), Fe (iron), Zn (zinc), and C (carbon). Hereinafter, the at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C will also be simply referred to as an additive. When the first layer 31 contains such an additive, the resistivity of the first layer 31 is higher than the resistivity of the second layer 32 and the resistivity of the third layer 33. Therefore, it is difficult for a current to take a path (schematically represented by arrow A in FIG. 1 ) from the third electrode 73, which is the anode of the first light-emitting unit 101, to the second electrode 72, which is the cathode of the second light-emitting unit 102. Therefore, the leakage current flowing between the third electrode 73 (anode) of the first light-emitting unit 101 and the second electrode 72 (cathode) of the second light-emitting unit 102 can be reduced.

[0033] The concentration of the additive contained in the first layer 31 is higher than the concentration of the additive contained in the second layer 32 and the concentration of the additive contained in the third layer 33. The first layer 31 may further contain a first conductivity type impurity. The concentration of the additive contained in the first layer 31 is higher than the concentration of the first conductivity type impurity contained in the first layer 31. This allows the electrons and holes to compensate for each other, making the first layer 31 more resistive and further reducing the leakage current.

[0034] The thickness of the first layer 31 is thinner than the thickness of the second layer 32 and the thickness of the third layer 33. The thickness of the first layer 31 is, for example, 100 nm or more and 1000 nm or less, or 200 nm or more and 600 nm or less. This makes it possible to reduce the absorption of light by the first layer 31 while increasing the electrical resistance of the first layer 31.

[0035] The first layer 31 preferably contains C as the additive. As will be described later, the first layer 31 can be formed by MOCVD (metal organic chemical vapor deposition). The concentration of C contained in the first layer 31 can be easily adjusted by adjusting the conditions at this time. Furthermore, compared to other additives, it is easier to increase the flatness of the first layer 31 while introducing C into the first layer 31. The C concentration in the first layer 31 is higher than the C concentration in the second layer 32 and the C concentration in the third layer 33. This makes it possible to reduce the leakage current flowing between the electrodes of the multiple light-emitting units. The C concentration in the first layer 31 is, for example, 1×10 18 cm -3 More than 1×10 21 cm -3 Less than 1 x 10, preferably 19 cm -3 More than 1×10 20 cm -3 This makes it possible to reduce the influence of light absorption and also reduce the leakage current flowing between the electrodes of the plurality of light-emitting portions.

[0036] The concentration of C contained in the first layer 31 is higher than the concentration of the first conductivity type impurity (e.g., Si) contained in the first layer 31. This allows the first layer 31 to have a higher resistance, and the leakage current can be further reduced. The concentration of C contained in the first layer 31 may be 10 times or more and 1000 times or less, or 10 times or more and 100 times or less, of the concentration of the first conductivity type impurity contained in the first layer 31. Furthermore, the difference between the concentration of C contained in the first layer 31 and the concentration of Si contained in the first layer 31 is, for example, 9×10 17 cm -3 More than 1×10 20 cm -3 Less than 1 × 10 19 cm -3 More than 1×10 20 cm -3 This increases the resistance of the first layer 31.

[0037] The second layer 32 is located between the second nitride semiconductor layer 20 and the first layer 31. When the light-emitting element 1 includes the fifth nitride semiconductor layer 50, the second layer 32 is located between the fifth nitride semiconductor layer 50 and the first layer 31. The second layer 32 contains a first-conductivity-type impurity. The second layer 32 may also contain the additive. The concentration of the first-conductivity-type impurity contained in the second layer 32 is higher than the concentration of the additive contained in the second layer 32. This reduces the resistance of the second layer 32, and can reduce the forward voltage of the first light-emitting unit 101. The concentration of the additive contained in the second layer 32 is, for example, 1×10 16 cm -3 5x10 or more 18 cm -3 Below, 1×10 16 cm -3 More than 1×10 18 cm -3 or less, or 1×10 16 cm -3 More than 1×10 17 cm -3 The thickness of the second layer 32 is, for example, not less than 100 nm and not more than 2000 nm.

[0038] The third layer 33 is located between the first layer 31 and the second active layer 62, and contains a first conductivity type impurity. The third layer 33 may also contain the above-mentioned additive. The concentration of the first conductivity type impurity contained in the third layer 33 is higher than the concentration of the additive contained in the third layer 33. This reduces the resistance of the third layer 33, and can reduce the forward voltage of the second light-emitting unit 102. The concentration of the additive contained in the third layer 33 is, for example, 1×10 16 cm -3 5x10 or more 18 cm -3 Below, 1×10 16 cm -3 More than 1×10 18 cm -3 or less, or 1×10 16 cm -3 More than 1×10 17 cm -3 The thickness of the third layer 33 is, for example, not less than 100 nm and not more than 2000 nm.

[0039] The thickness of the third layer 33 is greater than the thickness of the second layer 32. This reduces the sheet resistance of the third layer 33, making it easier to diffuse current and reducing the forward voltage of the second light-emitting section 102. By making the second layer 32 thinner, crystal defects can be reduced. Furthermore, by making the second layer 32 thinner, when forming the second layer 32 by the MOCVD method, the time required for film formation can be shortened, thereby reducing thermal damage to layers below the second layer 32.

[0040] The thickness of the third layer 33 can be, for example, 0.5 to 1.2 times the thickness of the first nitride semiconductor layer 10. This allows a larger current to be injected into the second light emitting section 102, increasing the output. For example, when the thickness of the first nitride semiconductor layer 10 is 1 μm to 3 μm, the thickness of the third layer may be 0.5 μm to 3.6 μm, or 1 μm to 2 μm.

[0041] The concentrations of the additives in the first layer 31, the second layer 32, and the third layer 33 can be analyzed by SIMS (Secondary Ion Mass Spectrometry). Similarly, the concentrations of the first conductivity type impurities can also be analyzed by SIMS. For more detailed analysis, cross-sectional observation by a Transmission Electron Microscope (TEM) and elemental analysis by EDX (Energy Dispersive X-ray Spectroscopy) may be used in combination.

[0042] As shown in FIGS. 2A and 2B, the second layer 32 can have a first GaN layer 32A, a second GaN layer 32B, and a first AlGaN layer 32C. The second GaN layer 32B is located closer to the first layer 31 than the first GaN layer 32A. The second GaN layer 32B is located between the first AlGaN layer 32C and the first layer 31. The first AlGaN layer 32C is located between the first GaN layer 32A and the second GaN layer 32B. For example, the composition of the first AlGaN layer 32C may be Al x3 Ga 1-x3N may be (0.05 < x3 ≤ 0.4, preferably 0.05 ≤ x3 ≤ 0.2). Thereby, deterioration of the quality of the first AlGaN layer 32C can be reduced. The resistivity of the first AlGaN layer 32C is higher than the resistivity of the first GaN layer 32A and the resistivity of the second GaN layer 32B. Such a first AlGaN layer 32C functions as a resistance layer that reduces the leakage current flowing between the third electrode 73 (anode) of the first light-emitting portion 101 and the second electrode 72 (cathode) of the second light-emitting portion 102, similar to the first layer 31.

[0043] In the example shown in FIG. 2A, the first AlGaN layer 32C has a third connection surface 30A on which the third electrode 73 is disposed. The third electrode 73 is in contact with the first AlGaN layer 32C on the third connection surface 30A and is electrically connected to the first AlGaN layer 32C. Thereby, the leakage current flowing between the third electrode 73 (anode) of the first light-emitting portion 101 and the second electrode 72 (cathode) of the second light-emitting portion 102 is reduced.

[0044] In the example shown in FIG. 2B, the first GaN layer 32A has the third connection surface 30A. The third electrode 73 is in contact with the first GaN layer 32A on the third connection surface 30A and is electrically connected to the first GaN layer 32A. The contact resistance between the third electrode 73 and the first GaN layer 32A can be made lower than the contact resistance between the third electrode 73 and the first AlGaN layer 32C. Therefore, while reducing the forward voltage for causing the first light-emitting portion 101 to emit light, the leakage current flowing between the third electrode 73 (anode) of the first light-emitting portion 101 and the second electrode 72 (cathode) of the second light-emitting portion 102 is reduced.

[0045] As shown in FIGS. 3A and 3B, the third layer 33 can include a third GaN layer 33A, a fourth GaN layer 33B, and a second AlGaN layer 33C. The fourth GaN layer 33B is located farther from the first layer 31 than the third GaN layer 33A. The fourth GaN layer 33B is located between the second AlGaN layer 33C and the second active layer 62. The second AlGaN layer 33C is located between the third GaN layer 33A and the fourth GaN layer 33B. For example, the composition of the second AlGaN layer 33C is Al x4 Ga 1-x4N (0.05≦x4≦0.4, preferably 0.05≦x3≦0.2). This can reduce degradation in the quality of the second AlGaN layer 33C. The resistivity of the second AlGaN layer 33C is higher than the resistivity of the third GaN layer 33A and the resistivity of the fourth GaN layer 33B.

[0046] 3A, the second AlGaN layer 33C has a second connection surface 30B on which the second electrode 72 is disposed. The second electrode 72 is in contact with the second AlGaN layer 33C at the second connection surface 30B and is electrically connected to the second AlGaN layer 33C. In this case, the second AlGaN layer 33C, like the first layer 31, functions as a resistive layer that reduces the leakage current flowing between the third electrode 73 (anode) of the first light-emitting unit 101 and the second electrode 72 (cathode) of the second light-emitting unit 102. Therefore, the leakage current flowing between the third electrode 73 (anode) of the first light-emitting unit 101 and the second electrode 72 (cathode) of the second light-emitting unit 102 is reduced.

[0047] 3B, the third GaN layer 33A has a second connection surface 30B on which the second electrode 72 is disposed. The second electrode 72 contacts the third GaN layer 33A at the second connection surface 30B and is electrically connected to the third GaN layer 33A. The contact resistance between the second electrode 72 and the third GaN layer 33A can be made lower than the contact resistance between the second electrode 72 and the second AlGaN layer 33C.

[0048] The configuration of Fig. 2A may be combined with the configuration of Fig. 3A or 3B, or the configuration of Fig. 2B may be combined with the configuration of Fig. 3A or 3B.

[0049] [Second embodiment] The light-emitting element 2 according to the second embodiment will be described with reference to FIGS. 4 to 6B. As shown in FIG. 4, the light-emitting element 2 includes a first structure 401, a second structure 402, and a third structure 403.

[0050] <First structure 401> The first structure 401 includes a first laminated portion 201 , a first electrode 301 , and a second electrode 302 .

[0051] (First stacked portion 201) The first stacked layer 201 includes a first nitride semiconductor layer 210 containing first-conductivity-type impurities, a second nitride semiconductor layer 220 containing second-conductivity-type impurities, a first active layer 271 located between the first nitride semiconductor layer 210 and the second nitride semiconductor layer 220, and a third nitride semiconductor layer 230 located on the second nitride semiconductor layer 220 and containing the first-conductivity-type impurities. The second nitride semiconductor layer 220 is located between the first active layer 271 and the third nitride semiconductor layer 230. The first active layer 271 is a light-emitting layer that emits light and has, for example, an MQW structure. The first stacked layer 201 is a first light-emitting section.

[0052] The first nitride semiconductor layer 210 has a first surface 210A located on the opposite side to the interface with the first active layer 271. The light-emitting element 2 may have a substrate on the first surface 210A side. The first nitride semiconductor layer 210 also has a first connection surface 210B exposed from the third nitride semiconductor layer 230, the second nitride semiconductor layer 220, and the first active layer 271. The first connection surface 210B is located on the opposite side to the first surface 210A.

[0053] The third nitride semiconductor layer 230 has a third connection surface 230A located on the opposite side of the interface with the second nitride semiconductor layer 220.

[0054] (1st electrode 301) The first electrode 301 is disposed on the first connection surface 210 B of the first nitride semiconductor layer 210 and is electrically connected to the first nitride semiconductor layer 210 .

[0055] (Second electrode 302) The second electrode 302 is disposed on a third connection surface 230 A of the third nitride semiconductor layer 230 and is electrically connected to the third nitride semiconductor layer 230 .

[0056] The second electrode 302 functions as an anode of the first structure 401. The first electrode 301 functions as a cathode of the first structure 401. When a current is supplied to the first active layer 271 through the second electrode 302 and the first electrode 301, the first active layer 271 of the first structure 401 emits light. The emission peak wavelength of the first active layer 271 of the first structure 401 is a first wavelength. The first wavelength is, for example, not less than 440 nm and not more than 470 nm. Note that the range of the first wavelength is not limited to this.

[0057] <Second structure 402> The second structure 402 includes a second laminated portion 202 , a third electrode 303 , and a fourth electrode 304 .

[0058] (Second stacked portion 202) The second stacked layer 202 includes the first stacked layer 201, a fourth nitride semiconductor layer 240 containing second-conductivity-type impurities, a second active layer 272 located between the third nitride semiconductor layer 230 and the fourth nitride semiconductor layer 240, and a fifth nitride semiconductor layer 250 located on the fourth nitride semiconductor layer 240 and containing first-conductivity-type impurities. The fourth nitride semiconductor layer 240 is located between the second active layer 272 and the fifth nitride semiconductor layer 250. The second active layer 272 is a light-emitting layer that emits light and has, for example, an MQW structure. The second stacked layer 202 is a second light-emitting section.

[0059] The first laminated portion 201 of the first structure 401 and the first laminated portion 201 of the second structure 402 are positioned apart from each other with a first groove 901 in between. The first connecting surface 210B of the first structure 401 defines the bottom of the first groove 901. The width of the first groove 901 (i.e., the distance between the first laminated portion 201 of the first structure 401 and the first laminated portion 201 of the second structure 402) is, for example, not less than 1 μm and not more than 20 μm. In the light-emitting element 2 according to the second embodiment, when the width of the first groove 901 is relatively narrow in this way, insulation between the multiple light-emitting portions works effectively. The same applies to the second groove 902 described below.

[0060] The third nitride semiconductor layer 230 of the second structure 402 has a third connecting surface 230B. The third connecting surface 230B is exposed from the second active layer 272, the fourth nitride semiconductor layer 240, and the fifth nitride semiconductor layer 250. The third nitride semiconductor layer 230 has a first layer 231, a second layer 232, and a third layer 233. The detailed configurations of these layers 231 to 233 will be described later. The third connecting surface 230B is a partial surface of the third layer 233.

[0061] The fifth nitride semiconductor layer 250 has a fourth connecting surface 250A located on the opposite side to the interface with the fourth nitride semiconductor layer 240.

[0062] (Third electrode 303) The third electrode 303 is disposed on the third connection surface 230 B of the third nitride semiconductor layer 230 and is electrically connected to the third nitride semiconductor layer 230 .

[0063] (4th electrode 304) The fourth electrode 304 is disposed on a fourth connection surface 250 A of the fifth nitride semiconductor layer 250 and is electrically connected to the fifth nitride semiconductor layer 250 .

[0064] The fourth electrode 304 functions as an anode of the second structure 402. The third electrode 303 functions as a cathode of the second structure 402. When a current is supplied to the second active layer 272 through the fourth electrode 304 and the third electrode 303, the second active layer 272 of the second structure 402 emits light. The emission peak wavelength of the second active layer 272 of the second structure 402 is the second wavelength. The second wavelength is, for example, not less than 570 nm and not more than 590 nm. However, the range of the second wavelength is not limited to this.

[0065] <Third structure 403> The third structure 403 includes a third stacked portion 203 , a fifth electrode 305 , and a sixth electrode 306 .

[0066] (Third stacked portion 203) The third stacked layer 203 includes a first stacked layer 201, a second stacked layer 202, a sixth nitride semiconductor layer 260 containing second-conductivity-type impurities, and a third active layer 273 located between the fifth nitride semiconductor layer 250 and the sixth nitride semiconductor layer 260. The third active layer 273 is a light-emitting layer that emits light, and has, for example, an MQW structure. The third stacked layer 203 is a third light-emitting section.

[0067] The first laminated portion 201 of the second structure 402 and the first laminated portion 201 of the third structure 403 are positioned apart from each other across the second groove 902. The width of the second groove 902 (the distance between the first laminated portion 201 of the second structure 402 and the first laminated portion 201 of the third structure 403) is, for example, not less than 1 μm and not more than 20 μm.

[0068] The fifth nitride semiconductor layer 250 of the third structure 403 has a fifth connecting surface 250B. The fifth connecting surface 250B is exposed from the third active layer 273 and the sixth nitride semiconductor layer 260. The fifth nitride semiconductor layer 250 has a fourth layer 254, a fifth layer 255, and a sixth layer 256. The detailed configuration of each of these layers 254 to 256 will be described later. The fifth connecting surface 250B is a partial surface of the sixth layer 256.

[0069] The sixth nitride semiconductor layer 260 has a sixth connecting surface 260A located on the opposite side of the interface with the third active layer 273.

[0070] (5th electrode 305) The fifth electrode 305 is disposed on a fifth connecting surface 250 B of the fifth nitride semiconductor layer 250 and is electrically connected to the fifth nitride semiconductor layer 250 .

[0071] (6th electrode 306) The sixth electrode 306 is disposed on a sixth connecting surface 260 A of the sixth nitride semiconductor layer 260 and is electrically connected to the sixth nitride semiconductor layer 260 .

[0072] The sixth electrode 306 functions as an anode of the third structure 403. The fifth electrode 305 functions as a cathode of the third structure 403. When a current is supplied to the third active layer 273 through the sixth electrode 306 and the fifth electrode 305, the third active layer 273 of the third structure 403 emits light. The emission peak wavelength of the third active layer 273 of the third structure 403 is the third wavelength. The third wavelength is, for example, not less than 590 nm and not more than 770 nm. However, the range of the third wavelength is not limited to this.

[0073] A first wavelength of light emitted by the first active layer 271 of the first structure 401, a second wavelength of light emitted by the second active layer 272 of the second structure 402, and a third wavelength of light emitted by the third active layer 273 of the third structure 403 are different from one another. For example, the first wavelength is shorter than the second wavelength, and the second wavelength is shorter than the third wavelength.

[0074] The light emitted by the first active layer 271 of the first structure 401, the light emitted by the second active layer 272 of the second structure 402, and the light emitted by the third active layer 273 of the third structure 403 are extracted to the outside of the light-emitting element 2 mainly from the first surface 210A side of the first nitride semiconductor layer 210.

[0075] In the light-emitting element 2, the first active layer 271 of the first structure 401, the second active layer 272 of the second structure 402, and the third active layer 273 of the third structure 403 can each emit light individually. Furthermore, the light emissions of the first active layer 271 of the first structure 401, the second active layer 272 of the second structure 402, and the third active layer 273 of the third structure 403 can be individually controlled. Two active layers out of the first active layer 271 of the first structure 401, the second active layer 272 of the second structure 402, and the third active layer 273 of the third structure 403 can emit light simultaneously. Furthermore, all of the first active layer 271 of the first structure 401, the second active layer 272 of the second structure 402, and the third active layer 273 of the third structure 403 can emit light simultaneously. The first structure 401, the second structure 402, and the third structure 403 can form a single pixel that combines, for example, the three primary colors of RGB.

[0076] (Third nitride semiconductor layer 230 of second structure 402) The first layer 231, the second layer 232, and the third layer 233 of the third nitride semiconductor layer 230 of the second structure 402 will be described in detail.

[0077] The first layer 231 is located between the second layer 232 and the third layer 233. The first layer 231 contains the same additive as the first layer 31 of the first embodiment described above. Since the first layer 231 contains such an additive, the resistivity of the first layer 231 is higher than the resistivity of the second layer 232 and the resistivity of the third layer 233. Therefore, it is difficult for a current to take a path from the fourth electrode 304, which is the anode of the second structure 402, to the first electrode 301, which is the cathode of the first structure 401. Therefore, it is possible to reduce the leakage current flowing between the fourth electrode 304 (anode) of the second structure 402 and the first electrode 301 (cathode) of the first structure 401.

[0078] Furthermore, the first layer 231 can reduce the leakage current flowing between the second electrode 302, which is the anode of the first structure 401, and the third electrode 303, which is the cathode of the second structure 402.

[0079] Furthermore, the first layer 231 can reduce the leakage current flowing between the sixth electrode 306, which is the anode of the third structure 403, and the third electrode 303, which is the cathode of the second structure 402.

[0080] The concentration of the additive contained in the first layer 231 is higher than the concentration of the additive contained in the second layer 232 and the concentration of the additive contained in the third layer 233. The first layer 231 may further contain a first conductivity type impurity. The concentration of the additive contained in the first layer 231 is higher than the concentration of the first conductivity type impurity contained in the first layer 231. This allows the first layer 231 to have a higher resistance, and the leakage current can be further reduced.

[0081] The thickness of the first layer 231 is thinner than the thickness of the second layer 232 and the thickness of the third layer 233. The thickness of the first layer 231 is, for example, not less than 100 nm and not more than 1000 nm.

[0082] As described above, the first layer 231 preferably contains C as the additive in terms of ease of concentration adjustment and flatness. The C concentration of the first layer 231 is higher than the C concentration of the second layer 232 and the C concentration of the third layer 233. The C concentration of the first layer 231 is, for example, 1×10 18 cm -3 More than 1×10 21 cm -3 Less than 1 x 10, preferably 19 cm -3 More than 1×10 20 cm -3 This makes it possible to reduce the influence of light absorption and also reduce the leakage current flowing between the electrodes of the plurality of light-emitting portions.

[0083] The concentration of C contained in the first layer 231 is higher than the concentration of the first conductivity type impurity (for example, Si) contained in the first layer 231. This allows the first layer 231 to have a higher resistance, and the leakage current can be further reduced. The difference between the concentration of C contained in the first layer 231 and the concentration of Si contained in the first layer 231 is, for example, 9×10 17 cm -3 More than 1×10 20 cm -3 Less than 1 × 10 19 cm -3 More than 1×10 20 cm -3 The following is the result.

[0084] The second layer 232 is located between the second nitride semiconductor layer 220 and the first layer 231. The second layer 232 contains a first conductivity type impurity. The second layer 232 may also contain the above-mentioned additive. The concentration of the first conductivity type impurity contained in the second layer 232 is higher than the concentration of the additive contained in the second layer 232. This reduces the resistance of the second layer 232, thereby reducing the forward voltage of the second structure 402. The concentration of the additive contained in the second layer 232 is, for example, 1×10 16 cm -3 5x10 or more 18 cm -3 Below, 1×10 16 cm -3 More than 1×10 18 cm -3 or less, or 1×1016 cm -3 More than 1×10 17 cm -3 The following is the result.

[0085] The third layer 233 is located between the first layer 231 and the second active layer 272, and contains a first conductivity type impurity. The third layer 233 may also contain the above-mentioned additive. The concentration of the first conductivity type impurity contained in the third layer 233 is higher than the concentration of the additive contained in the third layer 233. This reduces the resistance of the third layer 233, and can reduce the forward voltage of the second structure 402. The concentration of the additive contained in the third layer 233 is, for example, 1×10 16 cm -3 5x10 or more 18 cm -3 Below, 1×10 16 cm -3 More than 1×10 18 cm -3 or less, or 1×10 16 cm -3 More than 1×10 17 cm -3 The following is the result.

[0086] The thickness of the third layer 233 is greater than the thickness of the second layer 232. This reduces the sheet resistance of the third layer 233, making it easier to diffuse current and improving the output of the second structure 402. By making the second layer 232 thinner, crystal defects can be reduced. Furthermore, by making the second layer 232 thinner, when forming the second layer 232 by the MOCVD method, the time required for film formation can be shortened, thereby reducing thermal damage to layers below the second layer 232. The thickness of the second layer 232 is, for example, not less than 100 nm and not more than 2000 nm. The thickness of the third layer 233 is, for example, not less than 100 nm and not more than 2000 nm.

[0087] (Fifth nitride semiconductor layer 250 of third structure 403) The fourth layer 254, the fifth layer 255, and the sixth layer 256 of the fifth nitride semiconductor layer 250 of the third structure 403 will be described in detail.

[0088] The fourth layer 254 is located between the fifth layer 255 and the sixth layer 256. The fourth layer 254 contains the same additive as the first layer 31 of the first embodiment described above. Because the fourth layer 254 contains such an additive, the resistivity of the fourth layer 254 is higher than the resistivity of the fifth layer 255 and the resistivity of the sixth layer 256. Therefore, it is difficult for a current to take a path from the sixth electrode 306, which is the anode of the third structure 403, to the third electrode 303, which is the cathode of the second structure 402, and to the first electrode 301, which is the cathode of the first structure 401. Therefore, it is possible to reduce the leakage current flowing between the sixth electrode 306 of the third structure 403 and the third electrode 303 of the second structure 402, and the leakage current flowing between the sixth electrode 306 of the third structure 403 and the first electrode 301 of the first structure 401.

[0089] The concentration of the additive contained in the fourth layer 254 is higher than the concentration of the additive contained in the fifth layer 255 and the concentration of the additive contained in the sixth layer 256. The fourth layer 254 may further contain a first conductivity type impurity. The concentration of the additive contained in the fourth layer 254 is higher than the concentration of the first conductivity type impurity contained in the fourth layer 254. This allows the fourth layer 254 to have a higher resistance, and the leakage current can be further reduced.

[0090] The thickness of the fourth layer 254 is thinner than the thickness of the fifth layer 255 and the thickness of the sixth layer 256. The thickness of the fourth layer 254 is, for example, not less than 100 nm and not more than 1000 nm.

[0091] As described above, the fourth layer 254 preferably contains C as the additive in terms of ease of concentration adjustment and flatness. The C concentration of the fourth layer 254 is higher than the C concentration of the fifth layer 255 and the C concentration of the sixth layer 256. The C concentration of the fourth layer 254 is, for example, 1×10 18 cm -3 More than 1×10 21 cm -3 Less than 1 x 10, preferably 19 cm -3 More than 1×10 20 cm -3 The following is the result.

[0092] The concentration of C contained in the fourth layer 254 is higher than the concentration of the first conductivity type impurity (for example, Si) contained in the fourth layer 254. This allows the fourth layer 254 to have a higher resistance, and the leakage current can be further reduced. The difference between the concentration of C contained in the fourth layer 254 and the concentration of Si contained in the fourth layer 254 is, for example, 9×10 17 cm -3 More than 1×10 20 cm -3 Less than 1 × 10 19 cm -3 More than 1×10 20 cm -3 The following is the result.

[0093] The fifth layer 255 is located between the fourth nitride semiconductor layer 240 and the fourth layer 254. The fifth layer 255 contains a first conductivity type impurity. The fifth layer 255 may also contain the above-mentioned additive. The concentration of the first conductivity type impurity contained in the fifth layer 255 is higher than the concentration of the additive contained in the fifth layer 255. This reduces the resistance of the fifth layer 255, thereby reducing the forward voltage of the third structure 403. The concentration of the additive contained in the fifth layer 255 is, for example, 1×10 16 cm -3 5x10 or more 18 cm -3 Below, 1×10 16 cm -3 More than 1×10 18 cm -3 or less, or 1×10 16 cm -3 More than 1×10 17 cm -3 The following is the result.

[0094] The sixth layer 256 is located between the fourth layer 254 and the third active layer 273 and contains a first conductivity type impurity. The sixth layer 256 may also contain the above-mentioned additive. The concentration of the first conductivity type impurity contained in the sixth layer 256 is higher than the concentration of the additive contained in the sixth layer 256. This reduces the resistance of the sixth layer 256, thereby reducing the forward voltage of the third structure 403. The concentration of the additive contained in the sixth layer 256 is, for example, 5×10 18 cm -3 Below, 1×10 18 cm -3Below, 1×10 17 cm -3 The following is the result.

[0095] The thickness of the sixth layer 256 is greater than the thickness of the fifth layer 255. This reduces the sheet resistance of the sixth layer 256, making it easier to diffuse current and improving the output of the third structure 403. By making the fifth layer 255 thinner, crystal defects can be reduced. Furthermore, by making the fifth layer 255 thinner, thermal damage to layers below the fifth layer 255 can be reduced when forming the fifth layer 255 by the MOCVD method. The thickness of the fifth layer 255 is, for example, not less than 100 nm and not more than 2000 nm. The thickness of the sixth layer 256 is, for example, not less than 100 nm and not more than 2000 nm.

[0096] As shown in FIGS. 5A and 5B , the third layer 233 may include a first GaN layer 233A, a second GaN layer 233B, and a first AlGaN layer 233C. The first GaN layer 233A is located between the first AlGaN layer 233C and the first layer 231. The second GaN layer 233B is located farther from the first layer 231 than the first GaN layer 233A. The first AlGaN layer 233C is located between the first GaN layer 233A and the second GaN layer 233B. The Al composition ratio of the first AlGaN layer 233C is higher than the Al composition ratio of the first GaN layer 233A and the Al composition ratio of the second GaN layer 233B. The resistivity of the first AlGaN layer 233C is higher than the resistivity of the first GaN layer 233A and the resistivity of the second GaN layer 233B. Like the first layer 231, such a first AlGaN layer 233C functions as a resistive layer that reduces the leakage current flowing between the fourth electrode 304, which is the anode of the second structure 402, and the cathodes of the other structures (the first electrode 301 and the fifth electrode 305).

[0097] 5A, the first AlGaN layer 233C has a third connection surface 230B on which the third electrode 303 is disposed. The third electrode 303 contacts the first AlGaN layer 233C at the third connection surface 230B and is electrically connected to the first AlGaN layer 233C.

[0098] 5B, first GaN layer 233A has third connection surface 230B. Third electrode 303 contacts first GaN layer 233A at third connection surface 230B and is electrically connected to first GaN layer 233A. The contact resistance between third electrode 303 and first GaN layer 233A can be made lower than the contact resistance between third electrode 303 and first AlGaN layer 233C.

[0099] As shown in FIGS. 6A and 6B , the sixth layer 256 can include a third GaN layer 256A, a fourth GaN layer 256B, and a second AlGaN layer 256C. The third GaN layer 256A is located between the second AlGaN layer 256C and the fourth layer 254. The fourth GaN layer 256B is located farther from the fourth layer 254 than the third GaN layer 256A. The second AlGaN layer 256C is located between the third GaN layer 256A and the fourth GaN layer 256B. The Al composition ratio of the second AlGaN layer 256C is higher than the Al composition ratio of the third GaN layer 256A and the Al composition ratio of the fourth GaN layer 256B. The resistivity of the second AlGaN layer 256C is higher than the resistivity of the third GaN layer 256A and the resistivity of the fourth GaN layer 256B. Like the fourth layer 254, such second AlGaN layer 256C functions as a resistive layer that reduces leakage current flowing between the sixth electrode 306, which is the anode of the third structure 403, and the cathodes of the other structures (the third electrode 303 and the first electrode 301).

[0100] 6A, the second AlGaN layer 256C has a fifth connection surface 250B on which the fifth electrode 305 is disposed. The fifth electrode 305 contacts the second AlGaN layer 256C at the fifth connection surface 250B and is electrically connected to the second AlGaN layer 256C.

[0101] 6B, third GaN layer 256A has fifth connection surface 250B on which fifth electrode 305 is disposed. Fifth electrode 305 contacts third GaN layer 256A at fifth connection surface 250B and is electrically connected to third GaN layer 256A. The contact resistance between fifth electrode 305 and third GaN layer 256A can be lower than the contact resistance between fifth electrode 305 and second AlGaN layer 256C.

[0102] The configuration of Fig. 5A may be combined with the configuration of Fig. 6A or 6B, or the configuration of Fig. 5B may be combined with the configuration of Fig. 6A or 6B.

[0103] The nitride semiconductor layers described in FIG. 1 may be provided between the second nitride semiconductor layer 220 and the third nitride semiconductor layer 230, and between the fourth nitride semiconductor layer 240 and the fifth nitride semiconductor layer 250, to form further tunnel junctions.

[0104] [Light-emitting device] A light emitting device 500 according to the embodiment will be described with reference to FIG.

[0105] The light emitting device 500 includes a wiring substrate 600 and one or more light emitting elements 1 arranged on the wiring substrate 600. In the example shown in FIG. 7, the light emitting element 1 of the first embodiment is shown as the light emitting element included in the light emitting device 500. The light emitting element 1 is arranged on the wiring substrate 600 with the surface on which the first electrode 71 to the fourth electrode 74 are arranged facing the wiring substrate 600. The light emitting device 500 may include multiple light emitting elements 1. In this case, the light emission of the multiple light emitting elements 1 can be individually controlled. The light emitting device 500 may include, for example, 1,000 or more or 10,000 or more light emitting elements 1 and may be used for vehicle headlights, etc. The light emitting device 500 may also be used in display devices such as displays. The light emitting element included in the light emitting device 500 may be the light emitting element 2 of the second embodiment.

[0106] The wiring board 600 has an insulating base material 601, a first wiring portion 611, and a second wiring portion 612. The insulating base material 601 has a mounting surface 601A on which the light emitting element 1 is disposed. The first wiring portion 611 and the second wiring portion 612 are disposed on the mounting surface 601A of the insulating base material 601.

[0107] The third electrode 73 and the first electrode 71 of the light-emitting element 1 are electrically connected to the first wiring portion 611. The first wiring portion 611 supplies current to the third electrode 73 and the first electrode 71, causing the first active layer 61 of the first light-emitting portion 101 to emit light. The first wiring portion 611 has a first portion 611A electrically connected to the first electrode 71 and a third portion 611B electrically connected to the third electrode 73. The third electrode 73 and the first electrode 71 are joined to the first wiring portion 611 via a joining member 700 such as solder. Alternatively, the third electrode 73 and the first electrode 71 may be joined directly to the first wiring portion 611.

[0108] The fourth electrode 74 and the second electrode 72 of the light-emitting element 1 are electrically connected to the second wiring portion 612. The second wiring portion 612 supplies current to the fourth electrode 74 and the second electrode 72, causing the second active layer 62 of the second light-emitting portion 102 to emit light. The second wiring portion 612 has a fourth portion 612A electrically connected to the fourth electrode 74 and a second portion 612B electrically connected to the second electrode 72. The fourth electrode 74 and the second electrode 72 are joined to the second wiring portion 612 via a joining member 700 such as solder. Alternatively, the fourth electrode 74 and the second electrode 72 may be joined directly to the second wiring portion 612.

[0109] The light emitting device 500 emits visible light that is a mixture of light of a first wavelength from the first active layer 61 and light of a second wavelength from the second active layer 62. The light emitting device 500 emits, for example, white light. The color temperature (including the correlated color temperature) of the white light is, for example, 3000 K or more and 7000 K or less.

[0110] One example of a conventional light-emitting device that emits white light is one in which a wavelength conversion member containing a phosphor is placed over multiple light-emitting elements so as to straddle the multiple light-emitting elements, and white light is emitted by combining the light emitted by the light-emitting elements with light wavelength-converted by the wavelength conversion member. The phosphor is excited by the light from the light-emitting elements and emits light in all directions. Therefore, if one light-emitting element is activated and another light-emitting element adjacent to it is deactivated, the light from the phosphor located on the one light-emitting element may propagate to the non-emitting region on the other light-emitting element, reducing the contrast between the emitting and non-emitting regions. This reduction in contrast between the emitting and non-emitting regions may blur the contours of the light image created by the light-emitting device. Furthermore, light emitted by one light-emitting element may be scattered by the phosphor located on the one light-emitting element and propagate to the non-emitting region on the other light-emitting element. This may also reduce the contrast between the emitting and non-emitting regions.

[0111] On the other hand, the light emitting device 500 according to the embodiment does not include a wavelength conversion member containing a phosphor. The light emitting device 500 realizes white light by combining light of a first wavelength and light of a second wavelength emitted from the light emitting element 1. The light emitted from the light emitting element 1 has higher directionality than light emitted from a wavelength conversion member containing a phosphor. Therefore, when the light emission of multiple light emitting elements 1 is individually controlled, the light from the light emitting region of a driven light emitting element 1 is less likely to propagate to the non-light emitting region of other light emitting elements 1 that are not driven, resulting in highly directional light emission from the light emitting region, which can accentuate the contrast between the light emitting region and the non-light emitting region.

[0112] [Method of manufacturing light-emitting element] A method for manufacturing the light-emitting element 1 according to the first embodiment will be described with reference to FIGS.

[0113] 8, the method for manufacturing the light-emitting element 1 includes preparing a first light-emitting section 101 in which a first nitride semiconductor layer 10 containing a first conductivity-type impurity, a first active layer 61, and a second nitride semiconductor layer 20 containing a second conductivity-type impurity are sequentially stacked on a substrate 100. For example, the first light-emitting section 101 can be prepared by forming the first nitride semiconductor layer 10, the first active layer 61, and the second nitride semiconductor layer 20 sequentially on the substrate 100 by MOCVD in a furnace capable of adjusting the pressure and temperature.

[0114] The substrate 100 is placed in a processing chamber. In the MOCVD method, the substrate 100 is heated and raw material gases are introduced into the processing chamber to form each layer on the substrate 100. The substrate 100 may be, for example, a sapphire substrate.

[0115] The method for manufacturing the light-emitting element 1 includes, as necessary, forming a fifth nitride semiconductor layer 50 on the second nitride semiconductor layer 20 so that the concentration of the first conductivity type impurity is higher than that of the first nitride semiconductor layer 10 and the third nitride semiconductor layer 30 formed in a later step.

[0116] As shown in FIG. 9, the method for manufacturing the light-emitting device 1 includes forming a third nitride semiconductor layer 30 on the second nitride semiconductor layer 20. The third nitride semiconductor layer 30 is formed by, for example, an MOCVD method. The substrate 100 is heated and ammonia gas is introduced into a processing chamber to form the third nitride semiconductor layer 30. The third nitride semiconductor layer 30 contains at least N (nitrogen) and Ga (gallium). The ammonia gas is a source gas for N. Trimethylgallium or triethylgallium is further introduced into the processing chamber as a source gas for Ga to form the third nitride semiconductor layer 30.

[0117] During the formation of the third nitride semiconductor layer 30, at least one of the heating temperature of the substrate 100 and the flow rate of the ammonia gas is reduced. This makes it easier for C remaining in the process chamber and / or C from the Ga source gas to be introduced into the third nitride semiconductor layer 30, allowing the first layer 31 to be formed in the third nitride semiconductor layer 30. That is, the first layer 31 is formed on the second layer 32. During the formation of the third nitride semiconductor layer 30, the heating temperature of the substrate 100 may be reduced by 100°C or more and 200°C or less compared to the temperature used when forming the second layer 32. During the formation of the third nitride semiconductor layer 30, the flow rate of the ammonia gas may be reduced, for example, to 1% or more and 10% or less of the ammonia flow rate used when forming the second layer 32. During the formation of the third nitride semiconductor layer 30, the flow rate of the ammonia gas may be reduced, for example, to 0.1% or more and 0.5% or less of the ammonia flow rate used when forming the first nitride semiconductor layer 10. The first layer 31 is located between the second layer 32 and the third layer 33. The carbon concentration of the first layer 31 is higher than the carbon concentration of the second layer 32 and the carbon concentration of the third layer 33.

[0118] The heating temperature of the substrate 100 when the first layer 31 is formed is lower than the heating temperature of the substrate 100 when the second layer 32 is formed and the heating temperature of the substrate 100 when the third layer 33 is formed. Alternatively, the flow rate of the ammonia gas when the first layer 31 is formed is lower than the flow rate of the ammonia gas when the second layer 32 is formed and the flow rate of the ammonia gas when the third layer 33 is formed. Alternatively, the heating temperature of the substrate 100 and the flow rate of the ammonia gas when the first layer 31 is formed are lower than the heating temperature of the substrate 100 and the flow rate of the ammonia gas when the second layer 32 is formed and the heating temperature of the substrate 100 and the flow rate of the ammonia gas when the third layer 33 is formed.

[0119] 10, the method for manufacturing the light-emitting element 1 includes preparing a second light-emitting section 102 in which a second active layer 62 and a fourth nitride semiconductor layer 40 containing second-conductivity-type impurities are stacked in this order on a third nitride semiconductor layer 30. For example, the second light-emitting section 102 can be prepared by forming the second active layer 62 and the fourth nitride semiconductor layer 40 in this order on the third nitride semiconductor layer 30 by an MOCVD method.

[0120] 11 , the manufacturing method of the light-emitting element 1 includes etching the second light-emitting portion 102 and the first light-emitting portion 101 to expose the third nitride semiconductor layer 30 and the first nitride semiconductor layer 10. For example, using a resist mask, the second light-emitting portion 102 and the first light-emitting portion 101 are etched from the upper surface side of the fourth nitride semiconductor layer 40 by RIE (Reactive Ion Etching). By etching the second light-emitting portion 102 and the first light-emitting portion 101, a first connecting surface 10B is formed in the first nitride semiconductor layer 10. By etching the second light-emitting portion 102, a second connecting surface 30B and a third connecting surface 30A are formed in the third nitride semiconductor layer 30.

[0121] 1, the method for manufacturing the light-emitting element 1 includes arranging a first electrode 71 to a fourth electrode 74. The first electrode 71 is arranged on the first connection surface 10B, the second electrode 72 is arranged on the second connection surface 30B, the third electrode 73 is arranged on the third connection surface 30A, and the fourth electrode 74 is arranged on the fourth connection surface 40A, which is the upper surface of the fourth nitride semiconductor layer 40.

[0122] In the method for manufacturing light-emitting device 1, substrate 100 may be removed. Furthermore, in the method for manufacturing light-emitting device 1, first surface 10A of first nitride semiconductor layer 10 exposed by removing substrate 100 may be roughened.

[0123] As shown in FIG. 12, forming the third nitride semiconductor layer 30 can include forming GaN layers (first GaN layer 32A and second GaN layer 32B) and forming a first AlGaN layer 32C so as to be located midway between the GaN layers (first GaN layer 32A and second GaN layer 32B) before lowering at least one of the heating temperature of the substrate 100 and the flow rate of the ammonia gas, in other words, before forming the above-mentioned first layer 31.

[0124] As shown in FIG. 13, forming the third nitride semiconductor layer 30 can include forming GaN layers (third GaN layer 33A and fourth GaN layer 33B) and, after lowering at least one of the heating temperature of substrate 100 and the flow rate of ammonia gas, in other words, after forming the above-mentioned first layer 31, forming a second AlGaN layer 33C so as to be located midway between the GaN layers (third GaN layer 33A and fourth GaN layer 33B).

[0125] Under the same conditions, the etching rate of the AlGaN layer is slower than that of the GaN layer during RIE. Therefore, as shown in FIG. 12, by forming a first AlGaN layer 32C midway through the second layer 32 of the third nitride semiconductor layer 30, the change in etching rate can be used as a marker to easily stop the etching for forming the third connecting surface 30A in the second layer 32 at the desired depth. As shown in FIG. 2A, the etching may be stopped midway through the first AlGaN layer 32C. Alternatively, as shown in FIG. 2B, the etching may be stopped after passing through the first AlGaN layer 32C and reaching the first GaN layer 32A. At this time, the material changes from AlGaN to GaN, resulting in a faster etching rate. This change in etching rate serves as a marker for stopping the etching.

[0126] 13, by forming the second AlGaN layer 33C in the middle of the third layer 33 of the third nitride semiconductor layer 30, etching for forming the second connecting surface 30B in the third layer 33 can be easily stopped at a desired depth. As shown in FIG. 3A, the etching may be stopped in the middle of the second AlGaN layer 33C. Alternatively, as shown in FIG. 3B, the etching may be stopped after passing through the second AlGaN layer 33C and reaching the third GaN layer 33A.

[0127] The manufacturing method of the light-emitting element 2 of the second embodiment shown in Figure 4, similar to the manufacturing method of the light-emitting element 1 of the first embodiment, includes forming a stack of each layer of the light-emitting element 2 on a substrate, for example by an MOCVD method, and forming a first groove 901 and a second groove 902 in the stack formed on the substrate, for example by an RIE method.

[0128] As in the manufacturing method of the light-emitting element 1 of the first embodiment, the first layer 231 can be formed by lowering at least one of the heating temperature of the substrate and the flow rate of ammonia gas during the formation of the third nitride semiconductor layer 230, and the fourth layer 254 can be formed by lowering at least one of the heating temperature of the substrate and the flow rate of ammonia gas during the formation of the fifth nitride semiconductor layer 250.

[0129] When the first groove 901 and the second groove 902 are formed by the RIE method, deposits may adhere to the side surfaces of the first groove 901 and the second groove 902. These deposits may form paths for leakage current between the electrodes of the different structures 401 to 403. The first layer 231 and the fourth layer 254 can reduce leakage current that may flow through the deposits.

[0130] (Variation) FIG. 14 illustrates a light-emitting device 3 according to a modification of the first embodiment. The light-emitting device 3 differs from the light-emitting device 1 of the first embodiment in that the light-emitting device 3 includes a third light-emitting section 103 having a sixth nitride semiconductor layer 60 containing first-conductivity-type impurities, a seventh nitride semiconductor layer 70 containing second-conductivity-type impurities, and a third active layer 63 located between the sixth nitride semiconductor layer 60 and the seventh nitride semiconductor layer 70, all of which are disposed on a second light-emitting section 102. The light-emitting device 3 also differs from the light-emitting device 1 in that a fourth electrode 74 is disposed on a fourth connecting surface 60A of the sixth nitride semiconductor layer 60. The third active layer 63 is a light-emitting layer that emits light and has, for example, an MQW structure. A fifth electrode 75 is formed on a fifth connecting surface 60B of the sixth nitride semiconductor layer 60, and the fifth electrode 75 functions as a cathode for the third light-emitting section 103. A sixth electrode 76 is disposed on the sixth connecting surface 70 A of the seventh nitride semiconductor layer 70 , and functions as an anode of the third light emitting section 103 .

[0131] The sixth nitride semiconductor layer 60 includes a fourth layer 64, a fifth layer 65, and a sixth layer 66. The fourth layer 64 is located between the fifth layer 65 and the sixth layer 66. The fourth layer 64 contains the same additive as the first layer 31 of the first embodiment. Since the fourth layer 64 contains such an additive, the resistivity of the fourth layer 64 is higher than the resistivity of the fifth layer 65 and the resistivity of the sixth layer 66. This reduces the leakage current flowing between the fifth electrode 75 and the fourth electrode 74. The concentration of the additive contained in the fourth layer 64 is higher than the concentration of the additive contained in the fifth layer 65 and the concentration of the additive contained in the sixth layer 66. The fourth layer 64 preferably contains C as an additive. The C concentration of the fourth layer 64 may be in the same range as the C concentration of the first layer 31.

[0132] The thickness of the fourth layer 64 is less than the thickness of the fifth layer 65 and the thickness of the sixth layer 66. The thickness of the fourth layer 64 may be in a similar range to the thickness of the first layer 31. The thickness of the fifth layer 65 may be in a similar range to the thickness of the second layer 32. The thickness of the sixth layer 66 may be in a similar range to the thickness of the third layer 33. The thickness of the sixth layer 66 may be greater than the thickness of the fifth layer 65.

[0133] The concentration of the first conductivity type impurity contained in the fourth layer 64 may be in a range similar to the concentration of the first conductivity type impurity contained in the first layer 31. The concentration of the first conductivity type impurity contained in the fifth layer 65 may be in a range similar to the concentration of the first conductivity type impurity contained in the second layer 32. The concentration of the first conductivity type impurity contained in the sixth layer 66 may be in a range similar to the concentration of the first conductivity type impurity contained in the third layer 33.

[0134] The fifth layer 65 is located between the fourth layer 64 and the fourth nitride semiconductor layer 40 of the second light emitting section 102. The sixth layer 66 is located between the fourth layer 64 and the third active layer 63.

[0135] In the light-emitting element 3 according to the modified example, the first active layer 61 of the first light-emitting section 101 emits light at a first wavelength having a peak emission wavelength of 440 nm or more and 470 nm or less. The second active layer 62 of the second light-emitting section 102 emits light at a second wavelength having a peak emission wavelength of 570 nm or more and 590 nm or less. The third active layer 63 of the third light-emitting section 103 emits light at a third wavelength having a peak emission wavelength of 590 nm or more and 770 nm or less. The first wavelength, second wavelength, and third wavelength are all different. In the light-emitting element 3, the first layer 31 and the fourth layer 64 reduce leakage current between the light-emitting sections, allowing each light-emitting section to emit light individually. The light-emitting element 3 can emit light of a desired color by individually emitting each light-emitting section or by simultaneously emitting light from two or more light-emitting sections. The light-emitting element 3 may also emit white light by simultaneously emitting light from the first light-emitting section 101, the second light-emitting section 102, and the third light-emitting section 103.

[0136] As in the first embodiment, the fifth layer 65 may have, in order from the side closest to the fourth nitride semiconductor layer 40, a GaN layer, an AlGaN layer, and a GaN layer. Furthermore, the sixth layer 66 may have, in order from the side closest to the fourth layer 64, a GaN layer, an AlGaN layer, and a GaN layer.

[0137] The light-emitting element 3 may further include an eighth nitride semiconductor layer 80 located between the fourth nitride semiconductor layer 40 and the fifth layer 65. The eighth nitride semiconductor layer 80 contains first-conductivity-type impurities and forms an interface (p-n junction) with the fourth nitride semiconductor layer 40. The concentration of the first-conductivity-type impurities contained in the eighth nitride semiconductor layer 80 is in the same range as the concentration of the first-conductivity-type impurities contained in the fifth nitride semiconductor layer 50. This makes it possible to narrow the width of a depletion layer formed by the p-n junction between the fourth nitride semiconductor layer 40 and the eighth nitride semiconductor layer 80, and makes it easier for electrons present in the valence band of the fourth nitride semiconductor layer 40 to tunnel to the fifth layer 65.

[0138] (Current density versus voltage) In this example, the light-emitting element 1 shown in FIG. 1 was fabricated by MOCVD, and the light emission from the second light-emitting portion 102 was confirmed. The In content of the second active layer 62 was adjusted so that the second light-emitting portion 102 emitted light at a second wavelength of 570 nm or more and 590 nm or less. In this example, the third electrode 73 and the fourth electrode 74 were connected in common. FIG. 15 is a graph showing the behavior of current density versus voltage in the second light-emitting portion 102 of the light-emitting element 1. The graph shows that good characteristics were obtained. That is, it was found that there was good electrical conduction between the second electrode 72 and the fourth electrode 74, and that leakage between the second electrode 72 and the third electrode 73 was reduced.

[0139] (SIMS analysis) To investigate the behavior of the carbon concentration, SIMS analysis was performed on a wafer sample having the layer structure shown in FIG. 9 . During the formation of the third nitride semiconductor layer 30 by MOCVD, the heating temperature of the substrate 100 and the flow rate of ammonia gas were reduced to form the first layer 31. That is, the second layer 32 and the first layer 31 were formed in that order. The heating temperature of the substrate 100 when forming the first layer 31 was reduced by 170°C compared to the temperature when forming the second layer 32. The flow rate of ammonia gas was also reduced to 5% of the ammonia flow rate when forming the second layer 32. After the first layer 31 was formed to a predetermined thickness, the heating temperature of the substrate 100 and the flow rate of ammonia gas were restored to their original values to form the third layer 33. The introduction of the Si source material was interrupted when the first layer 31 was formed. The introduction of the Si source material was also restored to its original flow rate when the third layer 33 was formed.

[0140] Figure 16 shows the estimated values from SIMS analysis. 12 C and 28 1 is a graph showing the concentration of Si. The horizontal axis represents the depth, and the vertical axis represents 12 C and 28 The broken line represents the C concentration, and the solid line represents the Si concentration. In FIG. 16, the broken line represents the C concentration, and the solid line represents the Si concentration. The depth was calculated from the depth of the sputtering marks measured with a step gauge. The analyzed semiconductor layers are the third layer 33, the first layer 31, and the second layer 32, in that order from the surface side. The SIMS analysis was performed using primary ions (Cs +) was irradiated onto the sample. The primary ion acceleration voltage was set at two conditions: 2 keV and 15 keV. Figure 16 shows the results of converting the concentration of the secondary ion intensity of Si and C at an acceleration voltage of 15 keV. For the concentration conversion, a GaN layer with a known Si concentration and a GaN layer implanted with C ions were used as standard samples. However, for C, the concentration estimated at an acceleration voltage of 15 keV was converted to the concentration estimated at an acceleration voltage of 2 keV.

[0141] 16, it was confirmed that the C concentration increased sharply at the same time as the Si concentration decreased sharply. Therefore, it was found that the first layer 31, the second layer 32, and the third layer 33 can be distinguished by performing SIMS analysis.

[0142] The results of SIMS revealed that the C concentration in at least the first layer 31 was greater than the concentrations in the second layer 32 and the third layer 33. The C concentration in the first layer 31 was 2.64×10 19 cm ―3 The carbon concentration in the second layer 32 and the third layer 33 was estimated to be 2.18 × 10 18 cm ―3 However, the second and third layers 32 and 33, which have relatively low carbon concentrations, are affected by carbon from the atmosphere, so the absolute concentration values are uncertain. In measurements at an accelerating voltage of 15 keV, the carbon concentration in the second layer 32 could not be quantitatively analyzed due to the influence of the first layer 31, which has a higher carbon concentration. However, in measurements at an accelerating voltage of 2 keV, the carbon secondary ion intensity was similar in the second and third layers 32 and 33, so it was inferred that the carbon concentrations were also similar.

[0143] The Si concentration in the third layer 33 is 1.14×10 19 cm ―3 and the first layer 31 is 1.00×10 17 cm ―3 The second layer 32 is smaller, 1.11 x 10 19 cm ―3The Si concentration in the first layer 31 was equal to or lower than the background level.

[0144] Embodiments of the present invention can include the following light-emitting element, light-emitting device, and method for manufacturing a light-emitting element.

[0145] [Section 1] a first light emitting unit including a first nitride semiconductor layer containing a first conductivity type impurity, a second nitride semiconductor layer containing a second conductivity type impurity, and a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer; a second light emitting section located on the second nitride semiconductor layer, the second light emitting section having a third nitride semiconductor layer, a fourth nitride semiconductor layer containing second conductivity type impurities, and a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer; A first electrode; A second electrode; A third electrode; A fourth electrode; Equipped with The third nitride semiconductor layer is The first layer and a second layer located between the second nitride semiconductor layer and the first layer and containing a first conductivity type impurity; a third layer located between the first layer and the second active layer and containing a first conductivity type impurity; and the first layer contains at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C; the thickness of the third layer is greater than the thickness of the second layer; the first electrode is connected to the first nitride semiconductor layer; the second electrode is connected to the third layer; the third electrode is connected to the second layer; The fourth electrode is connected to the fourth nitride semiconductor layer. [Section 2] a first light emitting unit including a first nitride semiconductor layer containing a first conductivity type impurity, a second nitride semiconductor layer containing a second conductivity type impurity, and a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer; a second light emitting section located on the second nitride semiconductor layer, the second light emitting section having a third nitride semiconductor layer, a fourth nitride semiconductor layer containing second conductivity type impurities, and a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer; A first electrode; A second electrode; A third electrode; A fourth electrode; Equipped with The third nitride semiconductor layer is The first layer and a second layer located between the second nitride semiconductor layer and the first layer and containing a first conductivity type impurity; a third layer located between the first layer and the second active layer and containing a first conductivity type impurity; and the first layer contains C, and the C concentration in the first layer is higher than the C concentration in the second layer and the C concentration in the third layer; the first electrode is connected to the first nitride semiconductor layer; the second electrode is connected to the third layer; the third electrode is connected to the second layer; The fourth electrode is connected to the fourth nitride semiconductor layer. [Section 3] the second layer includes a first GaN layer, a second GaN layer, and a first AlGaN layer; the second GaN layer is located closer to the first layer than the first GaN layer; the first AlGaN layer is located between the first GaN layer and the second GaN layer; Item 3. The light-emitting device according to item 1 or 2, wherein the third electrode is connected to the first GaN layer or the first AlGaN layer. [Section 4] the third layer includes a third GaN layer, a fourth GaN layer, and a second AlGaN layer; the fourth GaN layer is located farther from the first layer than the third GaN layer; the second AlGaN layer is located between the third GaN layer and the fourth GaN layer; 4. The light-emitting device according to any one of items 1 to 3, wherein the second electrode is connected to the third GaN layer or the second AlGaN layer. [Section 5] 5. The light-emitting device according to any one of items 1 to 4, wherein the thickness of the third layer is 0.5 to 1.2 times the thickness of the first nitride semiconductor layer. [Section 6] the emission peak wavelength of the first active layer is a first wavelength; Item 6. The light-emitting device according to any one of items 1 to 5, wherein the emission peak wavelength of the second active layer is a second wavelength different from the first wavelength. [Section 7] the first wavelength is equal to or greater than 440 nm and equal to or less than 470 nm, Item 7. The light-emitting device according to item 6, wherein the second wavelength is 570 nm or more and 590 nm or less. [Section 8] a fifth nitride semiconductor layer located between the second nitride semiconductor layer and the second layer, forming an interface with the second nitride semiconductor layer, and containing first conductivity type impurities; 8. The light-emitting device according to any one of items 1 to 7, wherein a maximum value of the concentration of the first conductivity type impurity contained in the fifth nitride semiconductor layer is higher than a maximum value of the concentration of the first conductivity type impurity contained in the first nitride semiconductor layer and a maximum value of the concentration of the first conductivity type impurity contained in the third nitride semiconductor layer. [Section 9] the first layer comprises C; Item 9. The light-emitting device according to any one of items 1 to 8, wherein the carbon concentration in the first layer is higher than the carbon concentration in the second layer and the carbon concentration in the third layer. [Section 10] The C concentration of the first layer is 1×10 18 cm -3 More than 1×10 21 cm -3 Item 10. The light-emitting device according to item 2 or 9, wherein: [Section 11] A first structure, a second structure, and a third structure are provided, The first structure is a first stacked layer including a first nitride semiconductor layer containing first conductivity type impurities, a second nitride semiconductor layer containing second conductivity type impurities, a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer, and a third nitride semiconductor layer located on the second nitride semiconductor layer and containing first conductivity type impurities; a first electrode connected to the first nitride semiconductor layer; a second electrode connected to the third nitride semiconductor layer; and The second structure is a second stacked layer including the first stacked layer, a fourth nitride semiconductor layer containing second conductive type impurities, a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer, and a fifth nitride semiconductor layer located on the fourth nitride semiconductor layer and containing first conductive type impurities; a third electrode connected to the third nitride semiconductor layer; a fourth electrode connected to the fifth nitride semiconductor layer; and The third structure is a third stacked layer including the first stacked layer, the second stacked layer, a sixth nitride semiconductor layer containing second conductivity type impurities, and a third active layer located between the fifth nitride semiconductor layer and the sixth nitride semiconductor layer; a fifth electrode connected to the fifth nitride semiconductor layer; a sixth electrode connected to the sixth nitride semiconductor layer; and The third nitride semiconductor layer of the second structure is The first layer and a second layer located between the second nitride semiconductor layer and the first layer; a third layer located between the first layer and the second active layer; and the first layer contains at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C; the thickness of the third layer is greater than the thickness of the second layer; The fifth nitride semiconductor layer of the third structure is The fourth layer and a fifth layer located between the fourth nitride semiconductor layer and the fourth layer; a sixth layer located between the fourth layer and the third active layer; and the fourth layer includes at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C; the sixth layer has a thickness greater than the fifth layer; the first laminated portion of the first structure is a first light-emitting portion, the second laminated portion of the second structure is a second light-emitting portion, The third stacked portion of the third structure is a third light-emitting portion. [Section 12] the third layer includes a first GaN layer, a second GaN layer, and a first AlGaN layer; the second GaN layer is located farther from the first layer than the first GaN layer; the first AlGaN layer is located between the first GaN layer and the second GaN layer; Item 12. The light emitting device according to item 11, wherein the third electrode is connected to the first GaN layer or the first AlGaN layer. [Section 13] the sixth layer includes a third GaN layer, a fourth GaN layer, and a second AlGaN layer; the fourth GaN layer is located farther from the fourth layer than the third GaN layer; the second AlGaN layer is located between the third GaN layer and the fourth GaN layer; Item 13. The light-emitting device according to item 11 or 12, wherein the fifth electrode is connected to the third GaN layer or the second AlGaN layer. [Section 14] a wiring substrate having a first wiring portion that supplies a current between the third electrode and the first electrode, and a second wiring portion that supplies a current between the fourth electrode and the second electrode; One or more light-emitting elements according to any one of items 1 to 10, disposed on the wiring substrate; Equipped with A light emitting device that does not include a wavelength conversion member containing a phosphor. [Section 15] a wiring substrate having a first wiring portion that supplies a current between the third electrode and the first electrode, and a second wiring portion that supplies a current between the fourth electrode and the second electrode; One or more light-emitting elements according to any one of items 1 to 10, disposed on the wiring substrate; Equipped with the emission peak wavelength of the first active layer is a first wavelength; an emission peak wavelength of the second active layer is a second wavelength different from the first wavelength; A light emitting device that emits visible light that is a mixture of light of the first wavelength and light of the second wavelength. [Section 16] preparing a first light emitting unit in which a first nitride semiconductor layer containing a first conductivity type impurity, a first active layer, and a second nitride semiconductor layer containing a second conductivity type impurity are stacked in this order on a substrate; heating the substrate and introducing ammonia gas into a processing chamber to form a third nitride semiconductor layer on the second nitride semiconductor layer; preparing a second light emitting unit in which a second active layer and a fourth nitride semiconductor layer containing a second conductivity type impurity are stacked in this order on the third nitride semiconductor layer; etching the second light emitting section and the first light emitting section to expose the third nitride semiconductor layer and the first nitride semiconductor layer; Equipped with A method for manufacturing a light-emitting device, wherein at least one of the heating temperature of the substrate and the flow rate of the ammonia gas is reduced during the formation of the third nitride semiconductor layer. [Section 17] forming a fifth nitride semiconductor layer on the second nitride semiconductor layer so that the fifth nitride semiconductor layer has a higher concentration of first conductivity type impurities than the first nitride semiconductor layer and the third nitride semiconductor layer; Item 17. The method for manufacturing a light-emitting device according to item 16, wherein the third nitride semiconductor layer is formed on the fifth nitride semiconductor layer. [Section 18] The formation of the third nitride semiconductor layer includes: forming a GaN layer; forming a first AlGaN layer so as to be located midway through the GaN layer before at least one of the heating temperature of the substrate and the flow rate of the ammonia gas is reduced; Item 18. The method for producing a light-emitting device according to item 16 or 17, comprising: [Section 19] The formation of the third nitride semiconductor layer includes: forming a GaN layer; forming a second AlGaN layer in the middle of the GaN layer after reducing at least one of the heating temperature of the substrate and the flow rate of the ammonia gas; Item 18. The method for producing a light-emitting device according to item 16 or 17, comprising:

[0146] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that can be implemented by a person skilled in the art through appropriate design modifications based on the above-described embodiments of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention. In addition, a person skilled in the art may come up with various modifications and alterations within the scope of the concept of the present invention, and these modifications and alterations also fall within the scope of the present invention. [Explanation of symbols]

[0147] 1 to 3...light-emitting element, 10...first nitride semiconductor layer, 20...second nitride semiconductor layer, 30...third nitride semiconductor layer, 31...first layer, 32...second layer, 32A...first GaN layer, 32B...second GaN layer, 32C...first AlGaN layer, 33...third layer, 33A...third GaN layer, 33B...fourth GaN layer, 33C...second AlGaN layer, 40...fourth nitride semiconductor layer, 50...fifth nitride semiconductor layer, 60...sixth nitride semiconductor layer, 61...first active layer , 62...second active layer, 63...third active layer, 64...fourth layer, 65...fifth layer, 66...sixth layer, 70...seventh nitride semiconductor layer, 71...first electrode, 72...second electrode, 73...third electrode, 74...fourth electrode, 75...fifth electrode, 76...sixth electrode, 80...eighth nitride semiconductor layer, 100...substrate, 101...first light emitting portion, 102...second light emitting portion, 103...third light emitting portion, 201...first stacked portion, 202...second stacked portion, 203...third stacked portion, 210...th 1 nitride semiconductor layer, 220... second nitride semiconductor layer, 230... third nitride semiconductor layer, 231... first layer, 232... second layer, 233... third layer, 233A... first GaN layer, 233B... second GaN layer, 233C... first AlGaN layer, 240... fourth nitride semiconductor layer, 250... fifth nitride semiconductor layer, 254... fourth layer, 255... fifth layer, 256... sixth layer, 256A... third GaN layer, 256B... fourth GaN layer, 256C... second AlGa N layer, 260...sixth nitride semiconductor layer, 271...first active layer, 272...second active layer, 273...third active layer, 301...first electrode, 302...second electrode, 303...third electrode, 304...fourth electrode, 305...fifth electrode, 306...sixth electrode, 401...first structure, 402...second structure, 403...third structure, 500...light emitting device, 600...wiring substrate, 601...insulating base material, 611...first wiring portion, 612...second wiring portion, 700...bonding member

Claims

1. a first light emitting unit including a first nitride semiconductor layer containing a first conductivity type impurity, a second nitride semiconductor layer containing a second conductivity type impurity, and a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer; a second light emitting section located on the second nitride semiconductor layer, the second light emitting section having a third nitride semiconductor layer, a fourth nitride semiconductor layer containing second conductivity type impurities, and a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer; A first electrode; A second electrode; A third electrode; A fourth electrode; Equipped with The third nitride semiconductor layer is The first layer, a second layer located between the second nitride semiconductor layer and the first layer and containing a first conductivity type impurity; a third layer located between the first layer and the second active layer and containing a first conductivity type impurity; and the first layer includes at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C; the thickness of the third layer is greater than the thickness of the second layer; the first electrode is connected to the first nitride semiconductor layer; the second electrode is connected to the third layer; the third electrode is connected to the second layer; The fourth electrode is connected to the fourth nitride semiconductor layer.

2. the second layer includes a first GaN layer, a second GaN layer, and a first AlGaN layer; the second GaN layer is located closer to the first layer than the first GaN layer; the first AlGaN layer is located between the first GaN layer and the second GaN layer; The light-emitting element according to claim 1 , wherein the third electrode is connected to the first GaN layer or the first AlGaN layer.

3. the third layer includes a third GaN layer, a fourth GaN layer, and a second AlGaN layer; the fourth GaN layer is located farther from the first layer than the third GaN layer; the second AlGaN layer is located between the third GaN layer and the fourth GaN layer; The light-emitting element according to claim 1 , wherein the second electrode is connected to the third GaN layer or the second AlGaN layer.

4. 4. The light-emitting device according to claim 1, wherein the thickness of the third layer is 0.5 to 1.2 times the thickness of the first nitride semiconductor layer.

5. an emission peak wavelength of the first active layer is a first wavelength; The light-emitting device according to claim 1 , wherein the second active layer has a peak emission wavelength of a second wavelength different from the first wavelength.

6. the first wavelength is equal to or greater than 440 nm and equal to or less than 470 nm, The light-emitting element according to claim 5 , wherein the second wavelength is not less than 570 nm and not more than 590 nm.

7. a fifth nitride semiconductor layer located between the second nitride semiconductor layer and the second layer, forming an interface with the second nitride semiconductor layer, and containing first conductivity type impurities; 4. The light-emitting element according to claim 1, wherein a maximum value of the concentration of the first conductivity type impurity contained in the fifth nitride semiconductor layer is higher than a maximum value of the concentration of the first conductivity type impurity contained in the first nitride semiconductor layer and a maximum value of the concentration of the first conductivity type impurity contained in the third nitride semiconductor layer.

8. the first layer contains C, The light-emitting element according to claim 1 , wherein the first layer has a higher C concentration than the second layer and the third layer.

9. The C concentration of the first layer is 1×10 １８ cm －３ 1x10 or more ２１ cm －３ The light-emitting device according to claim 8 , wherein:

10. a first structure, a second structure, and a third structure; The first structure is a first stacked layer including a first nitride semiconductor layer containing first conductivity type impurities, a second nitride semiconductor layer containing second conductivity type impurities, a first active layer located between the first nitride semiconductor layer and the second nitride semiconductor layer, and a third nitride semiconductor layer located on the second nitride semiconductor layer and containing first conductivity type impurities; a first electrode connected to the first nitride semiconductor layer; a second electrode connected to the third nitride semiconductor layer; and The second structure is a second stacked layer including the first stacked layer, a fourth nitride semiconductor layer containing second conductive type impurities, a second active layer located between the third nitride semiconductor layer and the fourth nitride semiconductor layer, and a fifth nitride semiconductor layer located on the fourth nitride semiconductor layer and containing first conductive type impurities; a third electrode connected to the third nitride semiconductor layer; a fourth electrode connected to the fifth nitride semiconductor layer; and The third structure is a third stacked layer including the first stacked layer, the second stacked layer, a sixth nitride semiconductor layer containing a second conductivity type impurity, and a third active layer located between the fifth nitride semiconductor layer and the sixth nitride semiconductor layer; a fifth electrode connected to the fifth nitride semiconductor layer; a sixth electrode connected to the sixth nitride semiconductor layer; and The third nitride semiconductor layer of the second structure is The first layer, a second layer located between the second nitride semiconductor layer and the first layer; a third layer located between the first layer and the second active layer; and the first layer includes at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C; the thickness of the third layer is greater than the thickness of the second layer; The fifth nitride semiconductor layer of the third structure is The fourth layer, a fifth layer located between the fourth nitride semiconductor layer and the fourth layer; a sixth layer located between the fourth layer and the third active layer; and the fourth layer includes at least one selected from the group consisting of Be, Mg, Ca, Fe, Zn, and C; the sixth layer has a thickness greater than the thickness of the fifth layer; the first laminated portion of the first structure is a first light-emitting portion, the second laminated portion of the second structure is a second light-emitting portion, The third stacked portion of the third structure is a third light-emitting portion.

11. the third layer includes a first GaN layer, a second GaN layer, and a first AlGaN layer; the second GaN layer is located farther from the first layer than the first GaN layer; the first AlGaN layer is located between the first GaN layer and the second GaN layer; The light-emitting element according to claim 10 , wherein the third electrode is connected to the first GaN layer or the first AlGaN layer.

12. the sixth layer includes a third GaN layer, a fourth GaN layer, and a second AlGaN layer; the fourth GaN layer is located farther from the fourth layer than the third GaN layer; the second AlGaN layer is located between the third GaN layer and the fourth GaN layer; The light-emitting element according to claim 10 , wherein the fifth electrode is connected to the third GaN layer or the second AlGaN layer.

13. a wiring substrate including a first wiring portion that supplies a current between the third electrode and the first electrode, and a second wiring portion that supplies a current between the fourth electrode and the second electrode; One or more light-emitting elements according to any one of claims 1 to 3 arranged on the wiring substrate; Equipped with A light emitting device that does not include a wavelength conversion member containing a phosphor.

14. a wiring substrate including a first wiring portion that supplies a current between the third electrode and the first electrode, and a second wiring portion that supplies a current between the fourth electrode and the second electrode; One or more light-emitting elements according to any one of claims 1 to 3 arranged on the wiring substrate; Equipped with an emission peak wavelength of the first active layer is a first wavelength; an emission peak wavelength of the second active layer is a second wavelength different from the first wavelength; A light emitting device that emits visible light that is a mixture of light of the first wavelength and light of the second wavelength.

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